动态内存分配的应用：

 

 

 

#include <iostream>
#include <cmath>
using namespace std;
class Point{
public:
    Point(int newX=0,int newY=0){
        cout << "calling constructor" << endl;
        x=newX;
        y=newY;
    }
    Point(Point &p){
        x=p.x;
        y=p.y;
    }
    ~Point(){
        cout << "calling destructor " << endl;
    }
    void move(int x,int y){
        this->x+=x;
        this->y+=y;
    }
    int getX() {
        return x;
    }
    int getY() {
        return y;
    }
private:
    int x,y;
};
class PointsArray{
public:
    PointsArray(int size):size(size){
     array=new Point[size];  
    }
    Point &getElement(int index){
        if(index>=0&&index<size){
            return array[index];
        }
        else{
            cout << "invalid index!" << endl;
        }
    }
    ~PointsArray(){
       delete[] array;
    }
private:
    Point * array;
    int size;
};
int main(){
    Point *p=new Point(1,2);
    delete p;
     int n;
    cin>>n;
    PointsArray pa(n);
    cout<<pa.getElement(0).getX()<<" "<<pa.getElement(0).getY()<<endl;
    pa.getElement(1).move(1,1);
    cout<<pa.getElement(1).getX()<<" "<<pa.getElement(1).getY()<<endl;
    return 0;
}

输出结果：

　　　　calling constructor

　　　　calling destructor

动态内存分配：

new 数据类型（初始化形参列表）

int *point = new int;   //没有初值

int *point =new int(); //初值为0

int *a=new int[n];